Such appliances are generally mounted in a slot of standardized dimensions referred as “1 DIN” (from the DIN 75490/ISO 7736 standard), corresponding to an opening having dimensions of 180 millimeters (mm)×50 mm.
To mount the car radio, the technique consists in placing a generally metal mounting sheath that is snap-fastened, or fastened in any other appropriate way, inside the opening provided for this purpose in the dashboard (or the central console or any other suitable location). The metal sheath is generally left permanently in the opening and serves as an internal support and guide for inserting the car radio in the dashboard.
Once the sheath has been installed, the car radio is inserted and snap-fastened therein. Snap-fastening is performed by means of anti-return spring tongues such that once the car radio housing has been put into place it cannot be withdrawn from its position without using a suitable dismounting tool.
The dismounting tool is generally constituted by U-shaped keys having two branches in the form of needles that are inserted into orifices provided in the front face of the car radio housing in order to separate the car radio housing from the metal sheath: on being inserted, the needles press against the spring tongues, thereby pushing them back and releasing the housing so that it can be extracted freely from the sheath.
That mounting system requires orifices to be provided for inserting the dismounting tool, which orifices are usually two or four in number and disposed symmetrically at each side edge of the front face of the car radio housing.
By way of example, that mounting system is illustrated by U.S. Pat. No. 4,679,026 A (Blaupunkt-Werke GmbH), which describes a car radio having a flexible tongue fastener system on each of its left and right sides with two pairs of lateral orifices in its front face enabling a U-shaped key to be inserted to push back the tongues and separate the housing from the sheath.
The presence of these orifices is necessary in order to enable the car radio to be dismounted and extracted from the metal sheath in which it is fastened.
Orifices in the front face are very common in older models or in models forming part of the original equipment of a vehicle, but they are nevertheless relatively unattractive.
In other appliances, a plastics cover piece is provided that is fitted after mounting and snap-fastened to the sheath so as to overlie the peripheral edge of the car radio and hide these orifices. Nevertheless, that solution presents the two drawbacks of requiring an additional part and of being relatively unattractive insofar as it leaves visible an additional, relatively wide, and non-functional frame.
Finally, ergonomically speaking, the presence of orifices inevitably implies that a non-negligible area is occupied on either side of the front face of the housing, which area cannot be used for other purposes.
In particular, if it is desired to install a relatively large display on the car radio going all the way to the extreme edges of the housing, offsetting the display sideways prevents orifices from being incorporated in the housing for dismounting purposes. If a plastics cover hides such orifices, the presence of such a part likewise prevents a display being provided that extends to the edges of the car radio.
One possible solution consists in providing a dismountable front plate that is removably mounted on the housing.
An example of a car radio having a removable front plate is described for example in FR 2 920 945 A1 (Parrot S.A.). That removable front plate carries various control buttons for the car radio and acts as an anti-theft element; it may also serve to uncover a slot into which a compact disk can be inserted or, as in the above-mentioned application, a hatch into which it is possible to place a mobile telephone or a music player coupled to the car radio. Under such circumstances, the mounting orifices can be hidden behind the removable front plate.
The drawback of such removable front plates is their relatively large size, which means they are awkward to put into a pocket, for example.